roofing season is here and many contractors including ourselves get involved with several roofing projects in the fall for obvious reasons.
One of the key things i want to point out to homeowners is to never let a so called contractor talk you into whats called a "go over" or adding a second layer of shingles to your existing roof. Good contractors will not offer that service for several reasons, first off you' ll cut the life of the new shingles nearly in half in the picture i have provided below is a roof that was done less than 10 years ago A GO OVER, by a local roofing company that has since gone out of business. However there is another roofing company local (wont mention) names many people no who this person is that still to this day will try to talk consumers into a "go over" the bottom layer that has already failed now becomes your underlayment doesn't work. this post is simply to help folks that don't no about this. the house in this picture belongs to senior citizens and in my opinion were taken advantage of. best wishes to all. hope this has helped

Sorry to disagree but going over a single layer of shingles with a second one is common, even encouraged in the industry. I am not a professional but there is LOTS of impartial advice available. Building codes allow "go overs". Warranties allow it. It saves money. Of course it matters that the roof under the existing shingles is in good shape and the underlayment is not badly damaged. The existing roof also needs to be prepared properly, curled up shingles cleaned up, etc. A professional can do this well.

Just because a layer of shingles over another didn't age well doesn't disqualify the practice. I had a roof with a single layer of "30 year" shingles that looked bad at 12 years and had to be replaced at 15 years. Poor quality shingles are a common industry problem, even when they are from a supposedly good manufacturer.

I think it is more important that you know the reputation of the roofer and that he has been around for a while. If such a roofer recommended a second layer, I think it would be fine.

Sorry to disagree but going over a single layer of shingles with a second one is common, even encouraged in the industry. I am not a professional but there is LOTS of impartial advice available. Building codes allow "go overs". Warranties allow it. It saves money. Of course it matters that the roof under the existing shingles is in good shape and the underlayment is not badly damaged. The existing roof also needs to be prepared properly, curled up shingles cleaned up, etc. A professional can do this well.

Just because a layer of shingles over another didn't age well doesn't disqualify the practice. I had a roof with a single layer of "30 year" shingles that looked bad at 12 years and had to be replaced at 15 years. Poor quality shingles are a common industry problem, even when they are from a supposedly good manufacturer.

I think it is more important that you know the reputation of the roofer and that he has been around for a while. If such a roofer recommended a second layer, I think it would be fine.

It depends on how bad the first layer is. If they are brittle and coming apart then they need to come off.

The weight of one layer of shingles could add a couple thousand pounds to your roof. From what I've read it's about 250 lbs. per 10' X 10' area. If you don't remove the first layer when replacing it you are doubling the stress. When we have a lot of snow in the winter everyone is worrying about roof collapses and damage. Do you really want to add a few more thousand pounds in roofing on top of the existing weight?

The weight of one layer of shingles could add a couple thousand pounds to your roof. From what I've read it's about 250 lbs. per 10' X 10' area. If you don't remove the first layer when replacing it you are doubling the stress. When we have a lot of snow in the winter everyone is worrying about roof collapses and damage. Do you really want to add a few more thousand pounds in roofing on top of the existing weight?

There are a few factors to consider such as the pitch of your roof and the age of your home. There are many cases where roofing over an existing roof is fine. Then there are others that are questionable. It's always best to strip a roof but it's not always a must.

Sorry to disagree but going over a single layer of shingles with a second one is common, even encouraged in the industry. I am not a professional but there is LOTS of impartial advice available. Building codes allow "go overs". Warranties allow it. It saves money. Of course it matters that the roof under the existing shingles is in good shape and the underlayment is not badly damaged. The existing roof also needs to be prepared properly, curled up shingles cleaned up, etc. A professional can do this well.

Just because a layer of shingles over another didn't age well doesn't disqualify the practice. I had a roof with a single layer of "30 year" shingles that looked bad at 12 years and had to be replaced at 15 years. Poor quality shingles are a common industry problem, even when they are from a supposedly good manufacturer.

I think it is more important that you know the reputation of the roofer and that he has been around for a while. If such a roofer recommended a second layer, I think it would be fine.

Sorry to disagree but going over a single layer of shingles with a second one is common, even encouraged in the industry. I am not a professional but there is LOTS of impartial advice available. Building codes allow "go overs". Warranties allow it. It saves money. Of course it matters that the roof under the existing shingles is in good shape and the underlayment is not badly damaged. The existing roof also needs to be prepared properly, curled up shingles cleaned up, etc. A professional can do this well.

Just because a layer of shingles over another didn't age well doesn't disqualify the practice. I had a roof with a single layer of "30 year" shingles that looked bad at 12 years and had to be replaced at 15 years. Poor quality shingles are a common industry problem, even when they are from a supposedly good manufacturer.

I think it is more important that you know the reputation of the roofer and that he has been around for a while. If such a roofer recommended a second layer, I think it would be fine.

another reason why i dont post much on this site. have a good day

Why, do you get upset when someone disagrees with you? Relax, you can't take everything you read on an internet forum as the truth, the whole truth, and nothing but the truth.

Sky did work for me, did a great job and is a nice guy. For what it's worth, I agree with what he says and always have the old roof removed. Last roof I had done, the original builder of my house did not install the ice dam material he was supposed to install.

Well I do agree with the OP. When it comes to major house or camp maintenance projects I don't kick the can down the road. Do it right and live in peace for a long time. Off with the old, new ice guard and paper, new flashing and new shingles. Sleep well and dry for a long time.

Shingle over the old? That is a substantial weight subtracting from snow load margin. And what if that 30 year new roof only lasts 12? Now you really get to pay the piper.

BTW, my wife and I did the roof on our Welch Island cottage 15 years ago and we did it the right way. Extra work but done right, done once.

roofing season is here and many contractors including ourselves get involved with several roofing projects in the fall for obvious reasons.
One of the key things i want to point out to homeowners is to never let a so called contractor talk you into whats called a "go over" or adding a second layer of shingles to your existing roof. Good contractors will not offer that service for several reasons, first off you' ll cut the life of the new shingles nearly in half in the picture i have provided below is a roof that was done less than 10 years ago A GO OVER, by a local roofing company that has since gone out of business. However there is another roofing company local (wont mention) names many people no who this person is that still to this day will try to talk consumers into a "go over" the bottom layer that has already failed now becomes your underlayment doesn't work. this post is simply to help folks that don't no about this. the house in this picture belongs to senior citizens and in my opinion were taken advantage of. best wishes to all. hope this has helped

Thanks for the positive responses, this was posted to try and help people that may need a new roof I hate seeing folks being taken advantage of in this area of home improvements. Thanks again hope fully this has helped. Best wishes

Thanks for the positive responses, this was posted to try and help people that may need a new roof I hate seeing folks being taken advantage of in this area of home improvements. Thanks again hope fully this has helped. Best wishes

Thank you for the information. I have like you reccomend always have done complete replacements on replacing roofs for several reasons not mentioned. It is a great time to actually see if there had been any water issues from the original roofing and also as with everything technology has changed and its a great time to add snow and ice shielding if you do not already have it on your roof.

Just a easy fix tip fyi. When I last reroofed my house I noticed a lot of the failed shingles were where the sheathing butted together in between the framing because they warped away from each other. The pic below is not my roof but it shows what we noticed, cracked shingles on a horizontal lines through different shingles which indicated an issue with the sheathing. We needed to install "H" clips but how to install now? Easy. Just drilled a hole big enough to slip the h-clip through and slide over both sheets. Worked really slick and I thought I was pretty clever suggesting this to my roofer.

To tell the truth after the 1st layer has been on there for 20-30 years I'd rather pull 1st layer off to see what the roof is like. I've removed 1st layers from houses and found problems with the boards/plywood/drip edge etc. Will always pull off the 1st layer. More money yes, easy of mind priceless.
You know when you'll have a problem, right.

Just a easy fix tip fyi. When I last reroofed my house I noticed a lot of the failed shingles were where the sheathing butted together in between the framing because they warped away from each other. The pic below is not my roof but it shows what we noticed, cracked shingles on a horizontal lines through different shingles which indicated an issue with the sheathing. We needed to install "H" clips but how to install now? Easy. Just drilled a hole big enough to slip the h-clip through and slide over both sheets. Worked really slick and I thought I was pretty clever suggesting this to my roofer.

Adding H clips when the sheathing never had them and there is no space between each section will not do anything to create a space.
Drilling a hole just to slide the H clip in doesn't make sense.

H clips are spacers that go between each section of the sheathing before nailing it down and will create a space the full length.

One thing can be said for a roof "go-over" is that, "lost" roofing nails scattered around the drip line won't be found by little feet. Some designs are worse than others:

Quote:

Originally Posted by Dave M

To tell the truth after the 1st layer has been on there for 20-30 years I'd rather pull 1st layer off to see what the roof is like. I've removed 1st layers from houses and found problems with the boards/plywood/drip edge etc. Will always pull off the 1st layer. More money yes, easy of mind priceless. You know when you'll have a problem, right. Dave M

Seventy years later, a new owner added a second floor. The old 3/8ths-inch plywood roofing was carefully removed and stacked nearby. Aside from a few tar stains, all the plywood appeared in pretty good condition.

One factoid I learned from reading-up on plywood construction: in those days, the "glue" that held the plies together was cow's blood.

Most of the lumber bought today is garbage, young wood that rots very quickly.

I have notice lots of complaints about new constructions, (past 2 decades) is because of shoddy materials, not builders. They do go together at times.

I have seen new roofs replaced after a few years and battles with roofing manufacturers and installers as to who is at fault. A good engineer/project manager will tell you it can be both. Most new construction is all about time and money. Build them cheap and those who don't know will come!

I'm helping a new owner, just constructing a large home. Found lots of problems before the sidings and sheet rock goes up! Instead of fixing the problems the reputable 'Lakes Region Premier' builder is threatening to walk away! I feel sorry for the owner, who knows nothing about quality. Lesson to learn here is to work with a reputable project manager from the architectural stage. Even architects may not keep up with the times.

Lately I have seen excellent builds from prefab manufacturers such as BensenWoods out of Walpole. The materials are outstanding and the dollars per sq foot is competitive with stick built contractors. I have two customers use Bensonwoods as their contractor. WOW! I have learned a lot about quality materials and constructions. It pays to attend to details!

Adding H clips when the sheathing never had them and there is no space between each section will not do anything to create a space.
Drilling a hole just to slide the H clip in doesn't make sense.

H clips are spacers that go between each section of the sheathing before nailing it down and will create a space the full length.

You obviously dont know what h clips are used for based on your comment.
They are primarily for this:
If we place the H-clips at the halfway point (12") between the trusses and/or rafters, the adjoining sheathing panel stiffens
considerably. As a result, the fastening of the roof shingles will be easier and the roof will remain flatter and more “in plane” over time (i.e., no sags and/or bowing due to accumulated load).
They do also provide a small spacing for expansion if the sheahing gets wet before shingling but that is not what they really are for.It supports abutting plywood between rafters and keeps them from bowing in different directions.You might want to do a little research before you comment on something you seem to have little knowledge of.

I have notice lots of complaints about new constructions, (past 2 decades) is because of shoddy materials, not builders. They do go together at times.

I have seen new roofs replaced after a few years and battles with roofing manufacturers and installers as to who is at fault. A good engineer/project manager will tell you it can be both. Most new construction is all about time and money. Build them cheap and those who don't know will come!

I'm helping a new owner, just constructing a large home. Found lots of problems before the sidings and sheet rock goes up! Instead of fixing the problems the reputable 'Lakes Region Premier' builder is threatening to walk away! I feel sorry for the owner, who knows nothing about quality. Lesson to learn here is to work with a reputable project manager from the architectural stage. Even architects may not keep up with the times.

Lately I have seen excellent builds from prefab manufacturers such as BensenWoods out of Walpole. The materials are outstanding and the dollars per sq foot is competitive with stick built contractors. I have two customers use Bensonwoods as their contractor. WOW! I have learned a lot about quality materials and constructions. It pays to attend to details!

A lot of timber is cut before it fully matures now. If you use exterior trim boards now, esp pine, they will rot out within 5 years.
I built a new house 10 years ago and I tried to make it as maintenance free as possible. I use quality materials, vinyl siding and plastic for all the exterior trim pieces. I used Therma-tru exterior doors throughout the house and garage. At that time they didn't offer the doors trimmed out in plastic so I put them up as offered. I used 5 quality doors and the trim rotted out on all 5 doors within 5 years.
I built a deck on another house about tan years ago and did the railings in fur. They are all rotted out and need replacing.

Well can't blame a contractor for using products that are unknowingly problematic, a good example of that is the IKO shingle debacle from the late 90's where everyone was using them, they were at the time considered a premium product but they were fundamentally flawed thus leading to many premature failures and ultimately a class action law suit.

That said having previously worked in construction, roofing over is not best practice by any means and I have not heard of any shingle manufacturer that suggests this is a recommended solution. Can it be done, sure, but I wouldn't for a whole slew of reasons many previously mentioned. The GC I worked for would never do that because his reputation was on the line. Many however don't care will cut corners to hit a price point and obviously don't care about their client's well being. I'd betcha though none would do that on their own roof! Opinions on the subject obviously vary....

Far as those H clips go, I've only seen those used when the rafter spacing is such where they are required to prevent sheathing deflection under load. Far as I know there is little benefit to the spacing they introduce or better put not their intended purpose.

Far as those H clips go, I've only seen those used when the rafter spacing is such where they are required to prevent sheathing deflection under load. Far as I know there is little benefit to the spacing they introduce or better put not their intended purpose.

Good points & I agree.

I use a nail between the sheathing for spacing & it has worked fine for the many many roofs I have built. IMO you do need a space for expansion.

If the customer wants H clips than I would put them in (waste of money).

If you need H clips than IMO something is wrong with the rafter spacing or quality of the sheathing.

Most of the lumber bought today is garbage, young wood that rots very quickly.

Curious on your opinion about where to purchase quality lumber. I find that even buying a dozen 2X4's at Lowe's or Home Depot is near impossible. I will dig through a whole stack to find just 12 lousy boards that are straight (honestly the stack has been pawed through and all that i find are the garbage no one else wants, so I give up and leave).

Curious on your opinion about where to purchase quality lumber. I find that even buying a dozen 2X4's at Lowe's or Home Depot is near impossible. I will dig through a whole stack to find just 12 lousy boards that are straight (honestly the stack has been pawed through and all that i find are the garbage no one else wants, so I give up and leave).

Do you find that you have better luck at Non-Big-Box type stores?

I steer my customers to local lumber producers. One I like is Bartlett Lumber on 107. You still need to check the boards before loading on your truck.
May be a bit more expensive buying local, on the long run, well worth it!

If you insist on 'old growth' wood which are the best, find someone who needs an old barn torn down.
The value of old lumber is unbelievable, yet I seen greedy developers and builders tear or burn down these structures as they don't want to be bothered.

A lot of timber is cut before it fully matures now. If you use exterior trim boards now, esp pine, they will rot out within 5 years.
I built a new house 10 years ago and I tried to make it as maintenance free as possible. I use quality materials, vinyl siding and plastic for all the exterior trim pieces. I used Therma-tru exterior doors throughout the house and garage. At that time they didn't offer the doors trimmed out in plastic so I put them up as offered. I used 5 quality doors and the trim rotted out on all 5 doors within 5 years.
I built a deck on another house about tan years ago and did the railings in fur. They are all rotted out and need replacing.

If you were looking for extremely low maintenance fibrecrete is the way to go!
One Bensonwood home was built in 2007. Extremely low maintenance and the owner is very please with that fact! The roofing and siding materials are fiber cement materials. The Ramblin Vewe farmhouse siding is fiber cement and is now over 40 years old. Untouched and looks great!

Customers are extremely satisfied with Lowren windows and doors. Their stormforce series is perfect on the lake or on mountaintops!

On response to the roofing conversation being a licensed contractor for over 16 years. Yes the building code does allow you to go over the singles. But why? Like i tell the customer it may be cheaper now, but when you go to sell it will increase the value of the house. It will cost more money to strip 2 layers of shingles plus the disposal is twice as much. It is always better to sell a house and tell the buyer had the roof replaced so many years ago old shingles were removed. Any contractor going over the old shingles is out just for the money, has no quality in his work.

Thanks again for the reputable, professionals that gave there professional responses about "go overs" I simply did this to hopefully help folks that are perhaps dealing with the organic shingle issue or just need a new roof. The reality of finding a good full time roofer is nearly gone. The good roofers that did just roofing full time threw in there towels because let's face it most people look for the lowest price. when doing so make sure someone isn't selling you a second layer on your house in the long run it will cost you more. Nobody likes spending money on a roof it's not like building a new deck remodeling your kitchen however it's one of the most crucial elements to your home. Best wishes to all

Thanks again for the reputable, professionals that gave there professional responses about "go overs" I simply did this to hopefully help folks that are perhaps dealing with the organic shingle issue or just need a new roof. The reality of finding a good full time roofer is nearly gone. The good roofers that did just roofing full time threw in there towels because let's face it most people look for the lowest price. when doing so make sure someone isn't selling you a second layer on your house in the long run it will cost you more. Nobody likes spending money on a roof it's not like building a new deck remodeling your kitchen however it's one of the most crucial elements to your home. Best wishes to all

Thanks sky's..I agree with about not doing "go overs". Do it right the first time and also when new shingles are needed.
Best wishes to you & keep-up the good work!

Thanks for the positive responses, this was posted to try and help people that may need a new roof I hate seeing folks being taken advantage of in this area of home improvements. Thanks again hope fully this has helped. Best wishes

For the record I also agree with "Sky" and yes he's done work (roofing work actually) for my family and it came out great. Has also helped me out of a bind when I needed repairs done quickly after a storm. I'm no professional just agree with the theory of getting rid of the old and replacing with new.

Thanks sky's..I agree with about not doing "go overs". Do it right the first time and also when new shingles are needed.
Best wishes to you & keep-up the good work!

Here in Northern NJ, most towns no longer allow "go overs" in their building codes. In the past, you were allowed to do a go over as long as there was only 1 layer of shingles on the roof. Mine was redone about 20 years ago, and there were 2 layers of shingles on the 50+ year old home. Both these layers were removed and the sheathing underneath was in very good shape. It was shocking to see that the original shingles from 1941 were red and the 2nd layer was black. Went with light gray and they are still in good shape.

im glad this has reached out to many folks out there. Like i said in the original post there is a roofer locally that will try to sell you a go over this individual in my opinion is taking advantage of people for his on monetary gains. best wishes to all.

I can't stand go overs. When I did my roof last fall we discovered 2 layers on the sides and bottom, but up out of view from the road there were 8 layers on the roof. Snow load has never been a problem seeing as the roof is incredibly steep, and we discovered shingles we suspected were original to the house which was built in 1903.